Adjustable directional couplers are well known in the art for providing variable electromagnetic coupling between two transmission lines. In general, a mechanical motion of one or both of the conductors between which coupling occurs accomplishes the desired variation. However, the requirement that a portion of a transmission line be moveable may cause electrical instabilities and require physical bulk which are undesirable. In addition, prior art adjustable couplers are not readily integratible with a circuit which utilizes the coupled signal. For instance, it may be desired to variably sample a signal on a primary transmission line, to input the sampled signal into a circuit such as a power detector circuit and to output the resulting signal for various timing or other control purposes. This function is particularly difficult to achieve in space-limited devices such as fuzes and the like.